Omitempty

README.md

@@ -118,7 +118,8 @@ Other possible (optional) values are:
 * `seq` (slice field only): will treat field as a seq entry in the Augeas tree;
 * `key-from-value` (map field only): get the key from the node label instead
  of its value;
-* `purge` (map field only): purge all unknown keys in the map.
+* `purge` (map field only): purge all unknown keys in the map;
+* `omitempty`: do not set value when not found.
 
 
 ## Fields

parse.go

@@ -30,7 +30,7 @@ func (n *Narcissus) Parse(val interface{}) error {
 func (n *Narcissus) parseStruct(ref reflect.Value, path string) error {
  refType := ref.Type()
  for i := 0; i < refType.NumField(); i++ {
- if refType.Field(i).Name == "augeasPath" {
+ if strings.HasPrefix(refType.Field(i).Name, "augeas") {
  // Ignore the special `augeasPath` field
  continue
  }

tags.go

@@ -13,6 +13,7 @@ type fieldTags struct {
  keyFromLabel bool
  valueFromLabel bool
  seq bool
+ omitEmpty bool
 }
 
 func parseTag(tag reflect.StructTag) fieldTags {
@@ -24,6 +25,7 @@ func parseTag(tag reflect.StructTag) fieldTags {
  keyFromLabel: sliceHasTag(slice, "key-from-label"),
  valueFromLabel: sliceHasTag(slice, "value-from-label"),
  seq: sliceHasTag(slice, "seq"),
+ omitEmpty: sliceHasTag(slice, "omitempty"),
  }
 }
 

write.go

@@ -71,8 +71,7 @@ func (n *Narcissus) writeSimpleField(field reflect.Value, fieldPath string, tag
  return nil
  }
 
- // FIXME: use omitempty for that
- if value == "" {
+ if value == "" && parseTag(tag).omitEmpty {
  return nil
  }